1. Field of the Invention
The invention is directed to crystalline salt forms of a quinolinone-carboxamide compound which are useful as 5-HT4 receptor agonists. The invention is also directed to pharmaceutical compositions comprising such crystalline compounds, methods of using such compounds for treating medical conditions mediated by 5-HT4 receptor activity, and processes useful for preparing such compounds.
2. State of the Art
Commonly-assigned U.S. Provisional Application No. 60/560,076, filed on Apr. 7, 2004, and U.S. patent application Ser. No. 11/100,113, filed on Apr. 6, 2005, disclose novel quinolinone-carboxamide compounds that are expected to be useful for the treatment of disorders of reduced motility of the gastrointestinal tract. In particular, the compound 1-isopropyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid {(1S,3R,5R)-8-[(R)-2-hydroxy-3-(methanesulfonyl-methyl-amino)propyl]-8-azabicyclo[3.2.1]oct-3-yl}amide is specifically disclosed in these applications as demonstrating 5-HT4 agonist activity.
The chemical structure of 1-isopropyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid {(1S,3R,5R)-8-[(R)-2-hydroxy-3-(methanesulfonyl-methyl-amino)propyl]-8-azabicyclo[3.2.1]oct-3-yl}amide is represented by formula I:

To effectively use this compound as a therapeutic agent, it would be desirable to have a solid-state salt form that can be readily manufactured and that has acceptable chemical and physical stability. For example, it would be highly desirable to have a salt form that is thermally stable, for example at temperatures exceeding about 200° C., and is not hygroscopic nor deliquescent, thereby facilitating processing and storage of the material. Crystalline solids are generally preferred over amorphous forms, for enhancing purity and stability of the manufactured product.
No crystalline salt forms of the compound of formula I have previously been reported. Accordingly, a need exists for a stable, crystalline salt form of the compound of formula I that is neither hygroscopic nor deliquescent, and exhibits favorable thermal stability.